Prediction Of The Fracture Due To Mannesmann Effect In Tube Piercing

Fanini, Silvio; Ghiotti, Andrea; Bruschi, Stefania

doi:10.1063/1.2741006

Cited by 6 publications

(5 citation statements)

References 10 publications

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“…Using this ratio allows predicting the fracture location and identifying the main process parameters such as the number of rolls, the feed angle value, and some other parameters that affect the fracture, its value and location. The most known name for this ratio is "stress triaxiality" or "triaxiality" [8,12,[14][15][16]18]. The calculation of this value is realized in the QForm software:…”

Section: Resultsmentioning

confidence: 99%

Comparative analysis of damage criteria for screw rolling using computer simulation

Skripalenko¹,

Романцев²,

Галкин³

et al. 2020

cisisr

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Two-high screw rolling of billets was carried out using a MISIS-130D rolling mill. AISI 321 steel billets were deformed with feed angles of rolls of 6°, 12°, 18° and 24°. The diameter reduction was 17%, with the initial billets’ diameter being 60 mm. An axial fracture, the so-called Mannesmann effect, of the billets was observed after screw rolling. The experimental rolling was simulated using QForm finite element method software. Initial and boundary conditions were set in concordance with the experimental rolling. Several damage criteria were used for fracture prediction during computer simulation. The results of computer simulation of fracture prediction were compared with the billets fracture after screw rolling for stationary and non-stationary stages. The most effective parameter (in terms of fracture prediction) is triaxiality. The distribution of this parameter showed that the higher the feed angle value is, the lower the fracture risk is. Notably, the risk of fracture is lower at a stationary stage compared with the same risk of fracture at a non-stationary stage; the listed trends agree with experimental rolling results. The Oyane, Ayada, Brozzo, and Cockroft-Latham Normalized criteria are partly effective. These criteria are ineffective for fracture prediction 6 degrees feed angle of rolls because they showed that fracture is most probable at the billet’s surface, which contradicts the experimental rolling results. All these criteria are partly effective when predicting a less fracture risk at a stationary stage compared with the same criteria at a non-stationary stage or when predicting a decrease of fracture with increasing the rolls feed angle.

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Section: Resultsmentioning

confidence: 99%

Comparative analysis of damage criteria for screw rolling using computer simulation

Skripalenko¹,

Романцев²,

Галкин³

et al. 2020

cisisr

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“…Ceretti et al modelled crack opening using a Latham and Cockroft ductile damage model [4,5]. In the following years, Fanini and coworkers produced an in-depth study of the Mannesmann effect [6][7][8][9][10], explained it by the occurrence of a tensile stress in the direction normal to the compression by the rolls in the cross section. They focused on the onset of crack opening mechanism and therefore omitted the piercer plug in their simulations for simplicity.…”

Section: Rotation Axismentioning

confidence: 99%

“…They focused on the onset of crack opening mechanism and therefore omitted the piercer plug in their simulations for simplicity. Comparing several ductile damage models, they finally advocated a version of the Lemaitre model [8] and emphasized the impact of pre-existing porosity due to casting [6,9] or more generally of any metallurgical weakness or brittleness of the centreline of the billet. Starting from this conclusion, Skripalenko and coworkers recently studied the effect of the plug shape and more generally of the tooling on final shell porosity [11][12]; among the damage models, they promoted the normalized Latham and Cockroft one [13].…”

Section: Rotation Axismentioning

confidence: 99%

“…Comparing several ductile damage models, they finally advocated a version of the Lemaitre model [8]. They emphasized the impact of pre-existing porosity due to casting [6,9] or more generally of any metallurgical weakness or brittleness of the centerline of the billet. Starting from this conclusion, Skripalenko and coworkers recently studied the effect of the plug shape and more generally of the tooling on final shell porosity [11][12].…”

Section: Defect and Diffusion Forummentioning

confidence: 99%

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Identifying Heterogeneous Friction Coefficients on the Hot Forming Tools in Mannesmann Cross-Roll Piercing

Fernandes

Marouf

Montmitonnet

et al. 2022

DDF

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As in all metal rolling processes, Mannesmann cross-roll piercing relies on entrainment by friction between the billet and the rolls. But contrary to other rolling processes, a strong back-push is imposed by the piercing force (Fig. 1). Entrainment of the billet through the mill is therefore a critical problem which can be solved by optimizing the surface state of all tools (rolls, guide rolls, piercing plug). This is why the effect of friction with all the tools on the tube entrainment speed and on the state of stress has been investigated using the 3D Finite Element Method (FEM, ForgeNxT). It has been found that friction between billet and cross rolls is a driving force on the first (upstream) half of the rolls but may become resistant on the downstream part for certain process settings. Friction between piercer plug and hot metal is always resistant. Friction with rotating Diescher guide disks is a driving force in the piercing direction, but works against pierced shell rotation, causing shell torsion (“twist”). If static lateral guide shoes are preferred, their pure sliding friction is resistant in both directions. Friction on the upstream part of rolls must therefore be as high as possible for correct entrainment and process stability, which explains the practice of giving it very high roughness. The surface of the piercer plug must be smoother to minimize its frictional resistance. The surface states of lateral guides and of the downstream half of rolls can be used as process optimization variables. Results suggest how to obtain estimates of friction coefficients from mill measurements.

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“…Regarding the RTP process, the Hansel–Spittel law has been frequently used for the constitutive modelling of the billet material behaviour. Ghiotti and Fanini [ 23 , 24 , 25 ] modelled the flow stress of a DIN St52 steel in a skew rolling process with this formulation. Pschera et al [ 26 ] used this constitutive formulation for modelling the 10CrMo9-10 steel rheological behaviour during the RTP and the posterior analysis of material damage.…”

Section: Introductionmentioning

confidence: 99%

Application of an Incremental Constitutive Model for the FE Analysis of Material Dynamic Restoration in the Rotary Tube Piercing Process

Murillo-Marrodán

García

Barco³

et al. 2020

Materials

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In the numerical simulation of hot forming processes, the correct description of material flow stress is very important for the accuracy of the results. For complex manufacturing processes, such as the rotary tube piercing (RTP), constitutive laws based on both power and exponential mathematical expressions are commonly used due to its inherent simplicity, despite the limitations that this approach involves, namely, the use of accumulated strain as a state parameter. In this paper, a constitutive model of the P91 steel derived from the evolution of dislocation density with strain, which takes into account the mechanisms of dynamic recovery (DRV) and dynamic recrystallization (DRX), is proposed for the finite element (FE) analysis of the RTP process. The material model is developed in an incremental manner to allow its implementation in the FE code FORGE®. The success of this implementation is confirmed by the good correlation between results of the simulation and experimental measurements of the manufactured tube (elongation, twist angle, mean wall thickness and eccentricity). In addition, this incremental model allows addressing how the restoring mechanisms of DRV and DRV occur during the RTP process. The analysis puts into evidence that DRV and DRX prevail over each other cyclically, following an alternating sequence during the material processing, due mainly to the effect of the strain rate on the material.

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Prediction Of The Fracture Due To Mannesmann Effect In Tube Piercing

Cited by 6 publications

References 10 publications

Comparative analysis of damage criteria for screw rolling using computer simulation

Comparative analysis of damage criteria for screw rolling using computer simulation

Identifying Heterogeneous Friction Coefficients on the Hot Forming Tools in Mannesmann Cross-Roll Piercing

Application of an Incremental Constitutive Model for the FE Analysis of Material Dynamic Restoration in the Rotary Tube Piercing Process

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